1. Field of the Invention
This invention relates to reproduction apparatus in general and, more specifically, the invention relates to improved document sheet feeding apparatus for presenting multiple sheet simplex or duplex documents to a copier/duplicator to make collated sets of copies of such documents and for presenting an individual document sheet to the copier along another path to make individual or multiple copies of the individual document sheets.
2. Description of the Prior Art
Copier/duplicators typically comprise a platen against which an original document is positioned for copying by exposing the document while on the platen and projecting an image of the document onto a photoconductor where the image is developed. The image then is transferred to a copy sheet and fused to the copy sheet. Document positioners are known for feeding individual document sheets to a platen for copying and then for feeding the sheets to a storage area. A typical feeder of this type is disclosed in U.S. Pat. No. 3,844,552 which issued on Oct. 29, 1974 in the names of Bleau et al. It is also known to provide recirculating document feeders which respectively feed individual sheets of a multi-sheet document from a stack to the platen and then away from the platen so that the copier produces collated sets of copies without collating apparatus. Examples of such document feeders are disclosed in the related copending U.S. Pat. Applications referenced above and in U.S. Pat. No. 27,976.
Recirculating document feeders as disclosed in such copending applications provide significant improvements in the copying operation, especially in regard to the convenience to the user and the ability to make collated sets of copies without the need for a collator. However, when a user wishes to make copies of an original document too large for the feeder, or when the original document is prepared by pasting or otherwise assembling various portions of the document onto a backing sheet, the original may not feed reliably through the recirculating feeder. Also, some documents to be copied comprise one or only a few pages, and one or only a few copies of each page is required. In some cases the recirculating feeder can be stopped and then swung away from the platen to manually place directly onto the platen the page or pages of the document that are to be copied, and then one or more copies of the original can be made in the usual manner. One or more "master" copies can be made in this manner from documents not suitable for use in the recirculating feeder, and the "master" copies thus produced can be placed in the recirculating feeder in order to produce collated sets of copies. However, it is somewhat inconvenient to the machine operator to move the recirculating feeder away from the platen each time copies or "masters" are to be made in this manner, and the time required in converting from one mode of operation to another reduces the potential usage level of the copier. Clearly, it would be advantageous to be able to make copies from oversize originals, paste-up documents or from other documents without having to manually interrupt the job being run on the recirculating feeder, swing the feeder away from the platen, make the required number of copies of the oversize or paste-up originals, and then reposition and restart the recirculating feeder.
U.S. Pat. No. 4,062,533 to Greenberg, et al relates to a photocopy machine having a document feed module that jointly defines a straight line feed path leading to an exposure position. Document sheets can be fed to the feed path either manually or automatically, and the feed module can be swung away from the machine for copying of books and similar documents. However, there is no provision for automatic recirculation of document sheets.